Columnar cell variant of papillary thyroid carcinoma.

A 53-year-old woman was referred to our clinic for evaluation of a left anterior neck mass that was consistent with a thyroid goiter. She denied any systemic symptoms, and she was clinically euthyroid. Her only complaint was mild dysphagia of several months' duration, but she denied any significant weight loss.

On physical examination, the mass was firm and measured 4 x 5 cm. Computed tomography (CT) confirmed its location in the left thyroid lobe (figure 1). The mass appeared to be confined to the thyroid, and no pathologic cervical adenopathy was evident. Findings on fine-needle aspiration biopsy were indeterminate.

[FIGURE 1 OMITTED]

The patient was taken to the operating room, where she underwent a total thyroidectomy (figure 2). Final pathology identified the mass as a columnar cell variant of papillary thyroid carcinoma (PTC). The tumor was encapsulated and showed no evidence of extrathyroidal spread.

[FIGURE 2 OMITTED]

The columnar cell variant of PTC was first reported by Evans in 1986. (1) He described 2 patients with an aggressive tumor that rapidly metastasized and became fatal. Since then, several other cases have been reported. (2-5) In each patient, the progression of disease was similar. Also, unlike the case with most thyroid cancers, there was a strong male predominance with the columnar cell variant. These tumors also shared common histopathologic characteristics that are different from those of typical PTC. While the columnar cell variants did contain areas of papillary architecture, they were distinguished by the elongated (hence, "columnar") cells, whose nuclei were stratified and appeared to be rich in chromatin (figure 3, A). The classic nuclear features of PTC--including optical clearing, grooves, and inclusions (figure 3, B)--were rarely seen. The appearance of the columnar cells was similar to that of another subtype of PTC, the tall-cell variant, which was first reported by Hawk and Hazard in 1976. (6) Even so, histology revealed that the tall cells had more features in common with typical PTC than with the columnar cell variant.

[FIGURE 3 OMITTED]

The columnar cell variant has since been recognized by the World Health Organization as a distinct entity under the subheading of "aggressive variants" of PTC. (7) However, this classification is controversial because this disease has a tendency to metastasize hematogenously to the lungs and bones; therefore, many believe the columnar cell variant should be categorized as a subtype of follicular thyroid carcinoma. Others believe that the disease merits its own category as a specific type of thyroid carcinoma located along the spectrum of disease toward the poorly differentiated forms.

The columnar cell variant of PTC can pose a diagnostic challenge. (8) For example, it may be interpreted on initial fine-needle aspiration studies as typical PTC. Also, the microscopic appearance of a columnar cell specimen may lead a pathologist to consider metastatic adenocarcinoma. Immunohistochemical staining can be an important diagnostic aid in these cases; columnar cell variants of PTC should be negative for carcinoembryonic antigen and positive for thyroglobulin unless the cells are too poorly differentiated.

Controversy also surrounds the actual clinical course and prognosis of this disease. Both Evans (2) and Wenig et al (3) reported favorable prognoses in some patients--particularly with respect to the few cases that involved women. In most of these successfully treated cases, the tumors were encapsulated and had not undergone extrathyroidal invasion, and these patients survived without evidence of recurrent disease. In view of these findings, it has been suggested that the columnar cell variant should not necessarily be treated as an aggressive subtype of PTC; instead, treatment should be based on clinical staging, with a focus on tumor encapsulation and invasion beyond the confines of the thyroid gland. It is also possible that this particular tumor may have a greater tendency toward encapsulation in female patients, thus providing added protection from extrathyroidal invasion.

References

(1.) Evans HL. Columnar-cell carcinoma of the thyroid. A report of two cases of an aggressive variant of thyroid carcinoma. Am J Clin Pathol 1986;85:77-80.

(2.) Evans HL. Encapsulated columnar-cell neoplasms of the thyroid. A report of four cases suggesting a favorable prognosis. Am J Surg Pathol 1996;20:1205-11.

(3.) Wenig BM, Thompson LD, Adair CF, et al. Thyroid papillary carcinoma of columnar cell type: A clinicopathologic study of 16 cases. Cancer 1998;82:740-53.

(4.) Mizukami Y, Nonomura A, Michigishi T, et al. Columnar cell carcinoma of the thyroid gland: A case report and review of the literature. Hum Pathol 1994;25:1098-1101.

(5.) Perez F, Llobet M, Garijo G, et al. Fine-needle aspiration cytology of columnar-cell carcinoma of the thyroid: Report of two cases with cytohistologic correlation. Diagn Cytopathol 1998;18:352-6.

(6.) Hawk WA, Hazard JB. The many appearances of papillary carcinoma of the thyroid. Cleve Clin Q 1976;43:207-15.

(7.) Hedinger C, Williams ED, Sobin LH. Histological typing of thyroid tumours. 2nd ed. No. 11 in: International Histological Classification of Tumours, World Health Organization. Berlin: Springer-Verlag, 1988.

(8.) Jayaram G. Cytology of columnar-cell variant of papillary thyroid carcinoma. Diagn Cytopathol 2000;22:227-9.

Chester P. Barton III, MD; Joseph A. Brennan, MD; Thomas R. Lowry, MD; Michael J. Russell, MD

From the Department of Otolaryngology, U.S. Air Force Academy Hospital, Colorado Springs, Colo. (Dr. Barton); the Department of Otolaryngology-Head & Neck Surgery (Dr. Brennan) and the Department of Pathology (Dr. Russell), Wilford Hall, U.S. Air Force Medical Center, San Antonio, Tex; and the Department of Otolaryngology, Wright-Patterson Air Force Base Medical Center, Dayton, Ohio (Dr. Lowry). Originally presented as a poster during the annual meeting of the American Academy of Otolaryngology-Head and Neck Surgery; Sept. 19-22, 2004; New York City.

The opinions and assertions expressed in this article are those of the authors and do not reflect the views of the U.S. Air Force or the Department of Defense.